ABSTRACT
Radon is a naturally occurring radioactive gas produced by decay of radium. It is ubiquitous, appearing throughout the earth’s crust wherever uranium and thorium are found. Radon began to be recognized as a significant component of indoor air pollution only within the last two decades. It is now understood that inhaling radon decay products provides the dominant component of natural radiation exposure for the general public. Radon can spread throughout a building, decaying and producing its aerosolborne progeny everywhere. This chapter looks at the physics and chemistry that takes place when a radon or thoron atom undergoes radioactive decay. This decay is a very energetic event that results in the production of an atom different from the parent. The energy that is exchanged and the processes that occur while the new atom is adjusting to its environment can result in some unusual chemical and physical changes.
